Production of valuable hydrocarbons



M. PIER El' AL PRODUCTION OF VALUABLE -HYDROGARBONS Filed Aug. 17, .1951

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ratented heb. 12, 1935 PATENT *ori-*ics PRODUCTION .or VALUABLE maocaanoNs Mathias Pier, Heidelberg,

and Walter Rhin and Walterr Kroenig Simon, Ludwigshafen-on-the-A e. Germany, assigner-s to Standard-I. G. Company, Linden, N. J., a corporation oi' Dela- Application August 17, 1931., Serial No. 557,718

' In Germany August 22, 1930 11cm; (ci. 19e-5m l This invention relates to improvements in the production of valuable hydrocarbons.

It has already been proposed to use gases containing hydrogen, preferably in the presence of catalysts, in the preparaten of valuable hydro-A carbons from distillable oarbonaceous materials, L such ascoals, tars, mineral oils, their distillation and conversion products, by destructive hydrogenation at temperatures between 300 and '700 C., preferably betweenl i0057 and 550 C.. and lmder elevated pressures of at least 20 atmospheres,

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which hydrogenation may also be carried out under such mild conditions, that areilning of liquid mixtures of hydrocarbons from impurities.

.in particular from sulphur compounds without substantialsplitting of the hydrocarbons is effected. It has been found, however, that not all gases containing hydrogen obtained in industrial processes are directly employable for destructive hydrogenations; for example, when employing the gases containing hydrogen,obtained bythe degasiiication of ,solid fuels, under pressurfe and at elevated temperature, considerable difliculties, such as deposition of carbon or of solid or semi-solid high molecular carbon compounds, and a reduction in the hydrogeuating eiIect, are liable to occur.

We have now found. that these dimculties are due to the fact that gases obtained by the degasication of solidl bituminous materials, such as by the low temperature carbonization oi'brown and mineral coals, by the distillation of oil shales or by thepreparation of coke from mineral coal asv coke oven gas or illuminating gas,wh,en exposed to temperatures above 300 C. under increased pressure deposit carbonaceous substances,

by reason of the occurrence of polymeriaations ,f or vcondehsations of certain constituents, peculiar 'to the said'gases and these deposits lead to clogging up of the apparatus after operating for long periods f time.

on the basis or t imwleage, the dimensies* encountered when employing the gasa; obtained Nbythe.degasiilcationv of solid fuels as the hydrogenating gas are obviated according to the preseht invention byremoving from .the said gases before their employment those eon'stituents'which when heated'under pressure withthe initial myterials to be treated undergo' e rise 'to injuriouslreactious.

'changes' which gi as such or together su'ch as depositions or reduction of the hydrogenating action.

The said gases usually contain about 0.05 to 1 per cent of oxygen, from 0.1 to 0.5 gram oi organically combined sulphur per cubic meter of 5 gas,- the sulphur being mainly present as carbon dislphide and mercaptanes, and oxides of nitrogen in an amount of about 0.0001 per cent.

It has been found that in particular the unsaturated hydrocarbons, mainly those of strongly unsaturated nature, further free oxygen, the sulphur compounds and the oxides of nitrogen present in the said gases give rise to the said troubles and 'that it is therefore the chief problem to remove more or less completely these constituents 15 from the gases. l l

When the said gases are heated at atmospheric pressure. the formation of deposits is far less f than when they are heated under increased pressure, so that. when employing thegases at atmospheric pressure it is hardly necessary to remove the said substances.

The removal of the constituents which lead to the injurious deposits from the gasesmay be effected in diierent Ways,` as for example by employing agents, adsorbing the said constituents, chemical agents and/or catalysts at atmospheric or increased pressure.

For example solid adsorption agents, such as bleaching earth, active carbon, silica gel, andthe like may be employed, if desired at moderately elevated temperature, for example between- 150 and 300? C. l

The said adsorption agents remove part of -the organically combined sulphur, have a condensing action on dioleiines and promote thereaction between the oxides of nitrogen and diolefines to form high boiling products.

-Chemical agents may be employed instead of adsorptionagents. For example the unsaturated'v 40 hydrocarbons may be removed by washing with sulphuric acid, wherebyin order to econom'ize with acid, the concentration is preferably regulated so that the unsaturated hydrocarbons which react especially readily, namely the dioleflnes and acetylenes, are mainly removed while the more diilicultly decompjoaable, simple unsaturated I hydrocarbons are left in the gases. In this man- `.ner a part of the sulphurl compounds are removed at the Instead of. sulphuric acid, 5o

other reagents which react with unsaturated hydrocarbons and if desired also with sulphur compounds may be employed, as for example dilute nitric acid, alkaline hypochlorite solution and anhydrous aluminium chloride.

It has further been found that by leading the said gases over hydrogenating catalysts, such as those comprising ditllcultly reducible metal oxides of the 8th group of the periodic system, as for example oxides of molybdenum, tungsten, uranium or chromium, at atmospheric pressure and/or increased temperature (for example from about 350 to 400 C.) the said injurious constituents of the gases, chiefly the unsaturated hydrocarbons and the oxygen as well as any oxides of nitrogen present, are so far removed that the gases may then be directly employed in continuous operation at elevated temperatures even under increased pressure. The gases may also be treated at temperatures of, for example, from 200 to 300 C. with catalystscontaining silver, for example those obtained by precipitating salts of silver on carriers or those composed of salts of silver, 'such as silver chromate; in this manner the oxygen is removed almost entirely and the unsaturated hydrocarbons to such an extent that the gases maythen be heated to high temperatures without trouble. The removal of the oxygen and/or the unsaturated hydrocarbons may also be carried out with diiferent catalysts. Instead of treating the gases at high temperatures, for example between 350 and '100 C., under atmospheric pressure, the purincation may be carried out at moderately elevated temperatures, for example between 180 and 300 C., under increased pressures above 10 atmospheres, for example 25, 50, 100, 200, 500 or more atmospheres. Furthermore, the gases may be freed from injurious constituents by treatment in a liquid car- "bonaceous medium of high boiling point at temperatures of about 200 C. or more under pressure, as for example from 100 to 200 atmospheres, in the presence of catalysts, such as chromium, uranium or vanadium or compounds thereof, alone or in conjunction with each other or with other elements or compounds, as for example silver, zinc or compounds thereof and the like,

' or in the presence of catalysts forming methanol,

such as vanadic acid, manganese oxide, uranium oxide, titanic acid, chromic acid, zinc oxide, or mixtures of zinc oxide with uranium oxide, lead oxide, titanic acid, chromium oxide, or with chromium oxide and manganese oxide, and the like.

It has been found that gases purified in the said manner may be heated to reaction temperatures of for example from 300 to 500 C., even under a pressure of for example 200 atmospheres or more, for emple soo, 50o, soo or 1ooo amos-- for example by the said catalytic methods of purincation.

In addition to the said injurious impurities, the said gases usually contain small amounts of iron carbonyl by reason of their content of carbon monoxide. 'I'his-` iron carbonyl isfiable to be decomposed in the presence of the catalysts 1,oso,vos

with the formation of iron depositing on and thereby reducing the activity of the said catalysts. When these impurities are not removed by the pretreatment it is preferable to remove them before heatingv the gases, especially when catalysts are to be employed in the destructive hydrogenation processes and'this may be eii'ected in the usual manner, as for example by means of active carbon.

In some cases it may be advantageous to reduce the content of carbon ,dioxide and carbon monoxide in the gases, especially when catalysts, such as those containing molybdenum or iron, are to be employed in the destructive hydrogenation which decompose carbon monoxide with the formation of carbon black or which promote strongly the reduction of carbon oxides to methane, so that the heat evolved during the reduction is greater than is permissible for maintaining the desired reaction temperature during the destructive hydrogenation and, moreover, the concentration of methane in the gases becomes too high. Since, on the other hand, it may be advantageous in order to maintain the necessary reaction temperature, or in reactions which proceed with but a slight evolution of heat, that certain amounts of carbon monoxide or carbon dioxide should be present in the hydrogenating gas, the oxides of carbon are preferably only so far removed from the said gases that the residue'remaining is sufficient to give the desired evolution of heat during its conversion with hydrogen to form methane. As a rule the content of carbon monoxide and carbon dioxide should not be greater than 2 per cent.

The removal of the carbon dioxide may be effected by the usual methods, as for example by washing with water under pressure and the removal of the carbon monoxide by the usual methods of washing with solutions of cuprous salts. 'Furthermore, the amounts ofv carbon monoxide and carbon dioxide may be so far reduced byreduction to methane and water by the said purification of the gases by means of catalysts at 'amospherie pressure that they are present in the desired amount.

The gases freed from impurities which give rise to the formation of deposits may be employed for different processes for the destructive hydrogenation of carbonaceous substances, espe-l cially in the presence of catalysts. For example, the benzine obtained by the low temperature carbonization of brown coal maybe freed from the constituents which injuriously affect its employment in motors by catalytic` destructive hydrogenation with the purined low temperature Acarbonisation waste gases. The same result is obtained with the Ycrude benzene obtained by the -degasiilcation of mineral coals at high temperatures, for example between 900 and 1300 C., when it is treated with the coke oven or illumi nating gas formed at the same time, after it has been purified in the said manner. according to the present invention may also advantageously be employed, however, for other processes of destructive hydrogenation, such as the conversion of hydrocarbons of high boiling point into those of lower boiling point.

The hydrogenating gases, after their employment for the destructive hydrogenation, have an increased heating value by reason of their content of methane, which has been enriched during the reaction, and of 'gaseous hydrocarbons of high molecular weight, and, moreover, are practically free from carbon monoxide so that The process they may be 'advantageously employed as heating or illuminating gases. If the gases obtained from the destructive hydrogenation are to be rendered useful for the further treatment of carbonaceous materials, care should be taken by the removal of al part of the gaseous hydrocarbons that the partial pressure ofv hydrogenv is sufficiently high.

An apparatus suitable for carrying out ourV process is illustrated in diagrammatic form in the accompanying drawing, to which suitable descriptive legends have been applied. 'Ihe apparatus shown` is only one of various types in which our process could be carried out.- The manner in which our process is carried out in the apparatus shown in the drawing, is apparent from the following description. The illuminating gas entering pipe 1 is compressed to. for instance, 200 atmospheres, in compressor 2 and is led through active charcoal containing vessel 3. Thegas is then conveyed through iron-free pipe 3a, into heating coil 4 and there preheated at a temperature of 250 C. At this temperature itV enters the silver chromate containing vessel 5 and may be united in the T-piece 6 with any recycled hydrogenating gas. In th T-piece 7 the product which arrives by way of tank 9 and is compressed in pump 8 to, for example, 200 atmospheres, is mixed with the washed gas issuing from chamber 5a is preheated in coil 10 and then subjected to pressure hydrogenation or pressure rening in high-pressure hydrogenator 11. The reaction products which depart from the hydrogenator are cooled in cooling coil 12 and separated vinto liquid and gaseous products in separator 13. 'I'he liquid portions are released by way of valve 14 and removed from the system through pipe 15, whereas the gaseous portions leave through ,pipe16 and are either released in the pressure release valve 17 and removed by way of pipe 18, or else, as stated, are employed for the further treatment .of carbonaceous materials by following a circular course, in that they are conducted through pipe 16a into washing vessel 20 and there liberated from a part of the gaseous hydrocarbons by means oi' the oil pressed into the washer through pipe 21, which oil flows oi again through'pipe 19, and are re-conveyed into the reaction system by means of pump 2x2 to the T-piece 6.

The following example further illustrate the nature of this invention but the invention is not Festricted tov this example.

Example Illuminating gas, compressedto 200 atmospheres, is first led through a high-pressure container lled with active carbon and thus freed from iron carbonyl. 'I'he gas is then led through iron-free pipes into' a high-pressure chamber which is charged with acatalyst consisting of silver chromate deposited on silica-.g l. The chamber is kept at a temperature of 250 C. By this treatment the oxygen content of the illuminating. gas is reduced from 0.2 per cent to 0.01I per cent or less and the acetylene content is reduced from 0.06 per cent to 0.002 per cent or less. The oxides of nitrogen are converted almost com letely i nitrogen or ammonia and, water. The contf t of the other less unsaturated hydrocarbons and of the carbonimonoxide isr` practically .unreduced By -this treatment, condensation does not occur either beforehand or on the catalyst. After leaving the chamber the -gases and vapors leaving the reaction vessel are cooled, a product separates which can be refined to give a pure benzene mixture with only a very small waste, including the crude methanol formed catalytically Afrom the carbon monoxide and hydrogen contained in the illuminating gas. Neither in the preheating` chamber nor in the catalyst itself is there any condensationwhich injures the continuous operation.

Instead of the oxides of vanadium and zinc. the sulphides of these metals prepared by treatment of the metals or the oxides with volatile sulphur compounds in the presence of hydrogen at an elevated temperature and in the absence of hydrocarbons, or catalysts consisting of molybdic acid, zinc oxide and magnesia may also be employed with advantage. In this manner a considerably purer producty is obtained which need not be subjected to further purification. 'Ihe catalyst containing molybdenum has the further advantage that, by virtue of its capacity of promoting the partial conversion of the carbon monoxide contained in the illuminating gas into methane, a considerable amount of heat is evolved, which may be made useful for the maintenance of the reaction temperature.

If, on the contrany, the illuminating gas freed from iron carbonyl, is used directlyfor carrying out a. destructive hydrogenation or pressure rening without passing through the said purifying chamber, the preheating chamber becomes clogged up with deposits of condensation products similar to carbon black even after a few days so that continuous operation is impossible.

What we claim is:-

1. The process for destructively hydrogenating adistillable carbonaceous material with a hydrogenating gas obtained by the degasiflcation of a solid bituminous material, which comprises passing an impure gas from said source which may initially contain iron carbonyl over a catalyst having a hydrogenating action at a pressure ranging upwards from atmospheric pressure and a temperature of from 180 to 700 C.,'the temperature being within the range of 350 to 700 C. when the pressure is atmospheric and Within the range of 180 to 300 C. when the pressure exceeds atmospheric to thereby saturate any highly unsaturated hydrocarbons and convert any Acarbonyl in said impure gas being removed therefrom at any stage prior to the destructive hydrogenation, and eilecting the destructive hydro- .genation by contacting the thus purified gas with said carbonaceous material under a temperature and pressuresuitable for destructive.hydrogena-l tion and in the presence of a genation catalyst. Y

2. The process fordestructively hydrogenating a distillable carbonaceous material with a hydrogenating gas obtained destructive hydroby the degasication of a I solid bituminous material, which comprises pass-A ing an impure gas from said source which may initially contain iron carbonyl over a catalyst having a. hydrogenating action, at a temperature of about 350, to 700 C. and at atmospheric pressure to thereby saturate any lhighly unsaturated hydrocarbons and convert any lsulphur compounds, free oxygen, oxides of nitrogen and undesirable quantities of oxides o! carbon into readily removable and non-injln'ious inorganic substances, removing such of said inorganic substances as may be injurious, any iron carbonyl in said impure gas being removed therefrom at any stage prior to the destructive hydrogenation, and enecting the destructive hydrogenation by contacting the thus purified gas with said carbonaceous material under a temperature and pressure suitable fordestructive hydrogenation and in the presence of a destructive hydrogenation catalyst. Y 1

3. The process for destructively hydrogenating a distillable carbonaceous material with a hydrogenating gas obtained by the degasiiication of a. solid bituminous material which comprises passing' an impure gas from said source which may initially contain iron carbonyl over a catalyst having a hydrogenating action, at a temperature oi' about 180 to 300" C. and a pressure in excess of. 10 atmospheres to thereby saturate any highly unsaturated hydrocarbons and conany iron carbonyl in said impure gas being re.

moved therefrom at any stage prior to thedestructive hydrogenation, and eil'ecting the destructive hydrogenation by contacting the thus puriiied gas with said carbonaceous,v material under a temperature and pressure suitable for destruc ve hydrogenation and in the presence of a d tructive nvdrogenation catalyst.

4. Th process as deilned in claim 1 wherein the catalyst having a hydrogenating action is also immune to poisoning by sulphur.

5. The process as defined in claim 1 -wherein the catalyst lhaving a hydrogenating action comprises a metal oi' group 6 ot the periodic system.

6. 'Ihe process for destructively hydrogenating a distillable carbonaceous material with s hydrogenating gas ,obtained by' the degasiiication of a solid bituminous material which comprises passing an impure gas from said soin'cexwhich may initially contain iron carbonyl over a catalyst comprising an oxide of a metal of group 6 at a temperature of from 350 to 700 C. and at atmospheric pressure to thereby saturate any bishly unsaturated hydrocarbons and convert any sulphur compounds, freeomrgen, oxides of nitrogen and undesirable quantites oi oxides oi carbon into readily removable and non-injurious 11'1- organic substances, removing such ot said inorganic substances as may be injurious, any iron carbonyl in said impure gas being removed thmfrom at any stage `prior to the destructivehyd'rogenation, and electing the destructive hydrogenation by contacting the thus puriiied gas with said carbonaceousr material imder a temperature' .and pressure suitable for destructive hydrogenationandinthepresenceotadestructivehydrogenation catalyst.

7.'Iheprocessasdennedinclaim3wherein the catalyst having a hydrogenating action comprisesanoxideofametalotgrwpoottheperiodic system.

8. The process as denned in claim'i'wherein thecatalysthavingahydrogenatingactimcom- 9. 'l'.heprocessasdeiinedinclaimwhereinthel catalyst having a hydrogenating action comprises silver.

10. The process as denned in claim 3 wherein the catalysthaving a hydrogenating action comprises silver..

11. The process as defined in claim 1 wherein the temperature employed is selected from the range of 200 to 270 C., the pressure is at least 10 atmospheres and the catalyst having a hydrogenating action is silver chromate.

12. The process as denned in claim 1 wherein the temperature employed is selected from. the range of 200 to 270 C., the pressure is about 20.0 atmospheres and the catalyst having a hydrogenating action is silver chromate deposited on silica gel.

13. The process as defined in claim 6 wherein the degasiiication gas is treated with an adsorption agent prior to being passed over the catalyst having a hydrogenating action.

14. The process as defined in claim 8 wherein the degasiilcation gas is treated with sulphuric acid prior to being passed over a catalyst having a hydrogenating action.

15. The process for destructively hydrogenating a distillable carbonaceous material with a hydrogenating gas obtained by the degasiilcation of s soiid bituminous material which comprises treating an impure gas from said source containing iron carbonyl with active carbon to remove said iron carbonyl and then passing said gas over a catalyst comprising silver chromate at a temperature of from aboutI 200 to 270 C. and a pressure of at least 10 atmospheres to thereby saturate any highly unsaturated hydrocarbons and convert any sulphur compounds, free oxygen, oxides of nitrogen and undesirable quantities of oxides oi' carbon into readily removable and noninjurious inorganic substances, removing such ot said inorganic substances as may be injurious and con ting the thus puriiied gas with said carbo material under a temperature and pressure suitable for destructive hydrogenation and in the presencewoi' a destructive hydrogenation catalyst.

16. The process for destructively hydrogenating a distillable carbonaceous material with a hydrogenating gas obtained by the degasiilcation of a solid bituminous material which 'comprises removing\any iron carbonyl from gas from said source and passing said gas over a cataLvst comprising an oxide ot a metal oi group 6 of the periodic system at a pressure ranging upwards from 180 to 700 C., the temperature being within the range of 350 to 700' C. when the pressure is atmospheric and within the range of 180 to 300 C. when the pressure exceeds atmospheric to thereby saturate any highly unsaturated .hydrocarbons and convert any sulphur compounds, i'ree oxygen. oxides of nitrogen and undesirable quantities o! oxides of carbon into readily removable and non-injurious inorganic substancesl removing such of said inorganic substances as may be injurious and contacting the thus purined gas with said carbonaceous material under a temperature and pressure suitable for. destructive hydrogenation and in the presence of a destructive hydrogenation catalyst.

17. The process for destructively hydrogenatdrogenating gas obtained by the degasiiication of a solid bituminous material which'comprises'removing'any iron'carbonyl from an impure gas from said source and passing said gas over a catalyst comprising silver at a pressure ranging upwards from 180 ,to-700, C., the temperature being within the range of 350 to 700 C. when ing a distillable carbonaceous material with a hythe pressure is atmospheric and within the range -of 180 to 300 C. when the pressure exceeds atmospheric to thereby saturate any highly unsaturated hydrocarbons an'd convert any sulphur compounds, free oxygen, oxides of nitrogen and undesirable quantities of oxides of carbon into readily removable and non-injurious inorganic substances, removing such of said inorganic substances as may be injurious and contacting the thus puried gas with said carbonaceous material under a temperature and pressure suitable for destructive hydrogenation and in the presence of a destructive hydrogenation catalyst.

t MATHIAS PIER.

WALTER. KRJOENIG.l WALTER SIMON. 

